package com.hgx.springmvc.controller;

import com.hgx.springmvc.service.DeferredResultQueue;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.context.request.async.DeferredResult;

import java.util.UUID;
import java.util.concurrent.Callable;

@Controller
public class AsyncController {


    @ResponseBody
    @RequestMapping("/createOrder")
    public DeferredResult<Object> createOrder(){
        DeferredResult<Object> deferredResult = new DeferredResult<>((long)3000, "create fail...");

        DeferredResultQueue.save(deferredResult);

        return deferredResult;
    }


    @ResponseBody
    @RequestMapping("/create")
    public String create(){
        //创建订单
        String order = UUID.randomUUID().toString();
        DeferredResult<Object> deferredResult = DeferredResultQueue.get();
        deferredResult.setResult(order);
        return "success===>"+order;
    }

    /**
     * 1、控制器返回Callable
     * 2、Spring异步处理，将Callable 提交到 TaskExecutor 使用一个隔离的线程进行执行
     * 3、DispatcherServlet和所有的Filter退出web容器的线程，但是response 保持打开状态；
     * 4、Callable返回结果，SpringMVC将请求重新派发给容器，恢复之前的处理；
     * 5、根据Callable返回的结果。SpringMVC继续进行视图渲染流程等（从收请求-视图渲染）。
     *
     * preHandle.../springmvc-annotation/async01
     * 主线程开始...Thread[http-bio-8081-exec-3,5,main]==>1513932494700
     * 主线程结束...Thread[http-bio-8081-exec-3,5,main]==>1513932494700
     * =========DispatcherServlet及所有的Filter退出线程============================
     *
     * ================等待Callable执行==========
     * 副线程开始...Thread[MvcAsync1,5,main]==>1513932494707
     * 副线程开始...Thread[MvcAsync1,5,main]==>1513932496708
     * ================Callable执行完成==========
     *
     * ================再次收到之前重发过来的请求========
     * preHandle.../springmvc-annotation/async01
     * postHandle...（Callable的之前的返回值就是目标方法的返回值）
     * afterCompletion...
     *
     * 异步的拦截器:
     * 1）、原生API的AsyncListener
     * 2）、SpringMVC：实现AsyncHandlerInterceptor；
     *
     *
     */
    @ResponseBody
    @RequestMapping("/async01")
    public Callable<String> async01() {
        System.out.println("主线程开始..." + Thread.currentThread() + "==>" + System.currentTimeMillis());

        Callable<String> callable = new Callable<String>() {
            @Override
            public String call() throws Exception {
                System.out.println("副线程开始..." + Thread.currentThread() + "==>" + System.currentTimeMillis());
                Thread.sleep(2000);
                System.out.println("副线程开始..." + Thread.currentThread() + "==>" + System.currentTimeMillis());
                return "Callable<String> async01()";
            }
        };

        System.out.println("主线程结束..." + Thread.currentThread() + "==>" + System.currentTimeMillis());
        return callable;
    }
}
